Authorities in Brussels have slammed Facebook over its 2014 deal to buy WhatsApp for $19bn.

The EU competition commission has accused the tech giant of providing "misleading information" in connection with the deal in light of changes to the WhatsApp privacy policy announced in August.

Official charges, known as a Statement of Objections, have been filed against Facebook, with a potential fine of up to one per cent of profits if the complaint is upheld. Facebook has until 31 January to formally respond to the antitrust charges.

An investigation by the European watchdog found that the social network provided "incorrect or misleading information" during its investigation into its takeover of WhatsApp, approved in 2014.

"Companies are obliged to give the Commission accurate information during merger investigations. They must take this obligation seriously," said competition commissioner Margrethe Vestager.

"Our timely and effective review of mergers depends on the accuracy of the information provided by the companies involved. In this specific case, the Commission's preliminary view is that Facebook gave us incorrect or misleading information during the investigation into its acquisition of WhatsApp. Facebook now has the opportunity to respond."

An update to WhatsApp's privacy policy in August this year raised the prospect of linking account identities on both platforms to improve the service. However, in information given to the Commission when reviewing whether to give the merger the go ahead, the company said it would not be able to match accounts.

The response was just one of the factors taken into consideration in giving the deal the green light.

“We respect the Commission's process and are confident that a full review of the facts will confirm Facebook has acted in good faith," said a Facebook spokesperson.

"We've consistently provided accurate information about our technical capabilities and plans, including in submissions about the WhatsApp acquisition and in voluntary briefings before WhatsApp’s privacy policy update this year. We're pleased that the commission stands by its clearance decision, and we will continue to cooperate and share information officials need to resolve their questions."